62 



Conductivities and Viscosities in Pure and in Mixed Solvents. 



The constants given in table 35 are calculated from the values in 

 table 34. 



The ionization constants for methyl orange, recorded in tables 33 and 

 35, do not by any means represent the most accurate values that can be 

 obtained by this radiometric method. It is necessary that the meas- 

 urements be made in a region of the spectrum where the light energy is 

 not intense, and, consequently, the deflections of the radiomicrometer 

 are small. The largest deflection that could be obtained for wave- 

 lengths of light X = 0.58 M was 60 mm. It is for this reason that vibra- 

 tions, and variations in the intensity of the Nernst glower, seriously 

 interfere with the accuracy of the percentage transmissions. The 

 temperature which prevailed at the time these measurements were 

 made was not accurately known. However, it is certain that it was 

 between 20 and 23. The constants were calculated for 20; there- 

 fore, there is good reason to suppose that the real constants are some- 

 what higher (see table 37). 



TABLE 35. 



The transmission values given in table 36 were obtained when the 

 temperature at the time of measurement was known to be 20. The 

 measurements were made at night, when the building was fairly free 

 from vibrations. Under these conditions, the scale could be read 

 accurately to 0.25 mm. Except for solutions II and VI, the current 

 intensity remained very constant. A different mother solution of 

 methyl orange was used, its concentration being 3.054 X 10~ 4 gram- 

 molecules per liter. The concentration of the mother solution of sul- 

 phuric acid was 3.089 X10~ 4 gram-molecules per liter. 



